Intake apparatus of an engine

ABSTRACT

An intake apparatus of an engine(13) wherein an intake section(12) into which air flows from air cleaner is provided within an intake manifold(11), and a partition wall(16) defining a short intake passage(17) and a long intake passage(18) separately is installed concentrically with a circular intake manifold casing(15) with respect to the intake section(12), between the intake manifold casing(15) and the intake section(12). An intake control valve(20) is switchably arranged between an upper end(16a) of the partition wall(16) and a bent portion(14a) of the intake manifold(11). At least two unit shafts are spaced apart from and connected with each other to form a shaft(23) to which the intake control valve(20) is fixed. A driving mechanism(31) for driving the intake control valve(20) comprises an actuator(32) energized by a solenoid valve(41), a rod(33) connected to the actuator(32) and a lever(35) rotatably connected at its one end to the rod(33) by means of a pin and secured at its other end to the shaft(23).

TECHNICAL FIELD

The present invention relates to an intake apparatus of an engine, andmore particularly to an improved arrangement of an intake control valvefor switching intake passages in the intake manifold, and a drivingmechanism for driving the intake control valve.

BACKGROUND ART

Generally, it is well known that the output performance of an engineaccording to the revolutions of the engine depends upon the length ofintake passage formed in the intake manifold, that is, in case that theintake passage is made long, the output performance of the engine at lowspeed is raised due to the pulse effect of air, and where the intakepassage is made short, the output performance of the engine at highspeed is enhanced due to the inertia force of air.

Thus, there has been proposed an intake apparatus of an engine which iscapable of enhancing the output performance of the engine by making thelength of the intake passage of the intake manifold changeable andchanging the length of the intake passage in accordance with the changeof revolutions of the engine.

In a conventional intake apparatus, as shown in FIG. 2, both a shortintake passage 4 and a long intake passage 5 are separately providedwithin an intake manifold 1 to form intake passages each of whichextends from an intake section 2 to an intake port of an engine 3, andan intake control valve 6 is installed in the course of the short intakepassage 4 in such a manner that the intake control valve 6 may beswitched to close or open the intake passage 4 in accordance with therevolutions of the engine 3, thereby to allow air to flow into theengine 3 through the short intake passage 4 or the long intake passage5. However, such a conventional intake apparatus has defects in that thelong intake passage 5 is largely outwardly bent between the intakesection 2 and the engine 3, and therefore the volume of the apparatus asa whole is bulky, and in that the quick response to rapid accelerationor rapid deceleration of an automobile deteriorates.

Meanwhile, the intake control valve 6 is, as shown in FIGS. 1 and 3,secured to a shaft 9 by means of, for instance, screws 8, and the shaft9 is actuated by an actuator (not shown) in response to the operatingcondition of the engine so as to switch the intake control valve 6between the long intake passage 5 and the short intake passage 4,thereby to allow air to flow from the intake section 2 into the enginethrough the long intake passage 4 or the short intake passage 5.

However, where the conventional shaft 9 shown in FIG. 1 is thermallyexpanded due to high temperature of engine, the intake control valve 6contacts and interferes with the inner surface of the intake manifold 1,and as a result, the intake control valve 6 does not operate smoothly.Also, the conventional apparatus is disadvantageous in that a drivingmechanism for driving the shaft is complex.

DISCLOSURE OF INVENTION

The present invention aims to solve the abovementioned problems raisedin the conventional art.

It is therefore an object of the present invention no provide anapparatus of an engine with concise structure which is capable ofchanging the length of intake passage of an intake manifold, inaccordance with the revolutions of the engine.

Another object of the invention is to provide an apparatus of an enginein which an intake control valve shaft can absorb the thermal expansiondue to high temperature of the engine.

A further object of the invention is to provide an apparatus of anengine wherein a driving mechanism for driving an intake control valveis made compact.

To achieve these objects, an intake apparatus of the present inventionis characterized in that an intake section into which air flows from aircleaner is provided within an intake manifold, a partition wall isinstalled concentrically with an intake manifold casing surrounding theintake section with respect to the intake section, between the intakemanifold casing and the intake section in order to define a first intakepassage and a second intake passage separately, the first and secondintake passages having different lengths from each other, and an intakecontrol valve is switchably arranged between an upper end of thepartition wall and a bent portion of the intake manifold so as to allowair to flow from the intake section into the engine through the firstintake passage or the second intake passage.

And, the intake apparatus of the present invention is characterized inthat at least two unit shafts are spaced apart from and connected witheach other by means of a coupler to comprise a shaft to which the intakecontrol valve is fixed, thereby to absorb axial thermal expansion of theshaft due to the high heat of the engine.

Further, a driving mechanism for driving an intake control valveaccording to the present invention comprises an actuator activated by asolenoid valve, a rod connected to the actuator to move axially and alever rotatably connected at its one end to the rod by means of a pinand secured at its other end to the shaft.

By the present invention, it is possible to manufacture an intakeapparatus of an engine with simple structure having an intake controlvalve capable of changing the length of intake passages in the intakemanifold. And, since the thermal expansion of the shaft due to hightemperature of the engine can be absorbed, a reliable operation of theintake control valve is secured. Also, the driving mechanism for drivingthe intake control valve can be made concise and compact.

BRIEF DESCRIPTION OF DRAWINGS

The above objects and other features of the present invention will bemore apparent by describing the preferred embodiment thereof referringto the accompanying drawings, in which:

FIG. 1 is a perspective view of a conventional intake control valveshaft;

FIG. 2 is a schematic longitudinal sectional view of a conventionalintake manifold;

FIG. 3 is a sectional view of the conventional intake manifold, takenalong line A--A of FIG. 2;

FIG. 4A is a perspective view of an intake control valve shaft accordingto the present invention;

FIG. 4B is an enlarged perspective view of M of FIG. 4A;

FIG. 5A is a sectional view showing that the intake control valve shaftaccording to the invention is installed in an intake passage, similar toFIG. 3;

FIG. 5B is an enlarged view of N of FIG. 5A;

FIG. 6 is a cross sectional view of an intake apparatus of an engineaccording to the present invention;

FIG. 7 is a longitudinal sectional view of the intake apparatusaccording to the present invention;

FIG. 8 is a perspective view showing that a driving mechanism fordriving the intake control valve shaft according to the presentinvention is installed on the outer surface of the intake manifold;

FIG. 9A is a schematic view showing that the intake control valve is inits opened position to open the intake passage by the driving mechanismof FIG. 8;

FIG. 9B is a schematic view showing that the intake control valve is inits closed position to close the intake passage by the drivingmechanism; and

FIG. 10 is a schematic view showing the intake apparatus as a wholeaccording to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 6 and 7 are a cross-sectional view and a longitudinal-sectionalview of an intake apparatus of an engine according to one embodiment ofthe present invention, respectively. In FIG. 7, an intake manifold 11 isformed with an intake section 12 into which air flows from an aircleaner (not shown) and with a connecting passage 14 connected to theintake section 12 at its one end and to an engine 3 at its other end. Acasing 15 of the intake manifold 11 surrounding the intake section 12 issubstantially circular-shaped, and a curved partition wall 16 isarranged concentrically with the casing 15 with respect to the intakesection 12 in the intake manifold 11. The interior space of the casing15 is divided into a first intake passage 17 communicating directly withthe intake section 12 and a second intake passage 18 defined around theperiphery of the first intake passage 17, by means of the partition wall16. Between an upper end 16a of the partition wall 16 and a bent portion14a of the connecting passage 14 is a disc-type intake control valve 20installed rotatably in order to allow or block direct air-flow from theintake section 12 into the connecting passage 14. When the intakecontrol valve 20 is in the opened state, air flows from the intakesection 12 via the first intake passage 17 directly into the connectingpassage 14, whereas when the intake control valve 20 is in the closedstate, air flows from the intake section 12 via the second intakepassage into the connecting passage 14. As shown in FIG. 6, both theconnecting passage 14 and the intake passages 17 and 18 arelatitudinally divided into a plurality of connecting passages 14 andintake passages 17 and 18, respectively, by means of a plurality ofdivision walls 21. Accordingly, a plurality of intake control valves 20should be provided in the intake manifold 11. That is, each intakecontrol valve 20 is disposed in each intake passage 17, and each of thedivided connecting passages 14 is connected to the corresponding intakeport of the engine 13. And, each of the second intake passages 18divided by the division wall 21 is communicated with the connectingpassage 14 at one end thereof and with the intake section 12 at theother end thereof.

Referring to FIGS. 4A to 7, each of the intake control valves 20 issecured to a seat 25 formed on a shaft 23 by means of, for instance,screws 24. According to the features of the present invention, the shaft23 comprises at least two unit shafts 23a spaced apart from each other.Each of the unit shafts 23a is provided at one of the opposite endsthereof with a connection portion having a pair of semicircularprotrusions 23b which are apart from each other. The connection portionof one unit shaft 23a is connected to an adjacent connection portion ofadjacent unit shaft 23a with a pre-determined gap by means of coupler 26so as to absorb an axial thermal expansion of the shaft 23 caused byhigh temperature of the engine 13. Since a plurality of unit shafts 23aare firmly connected together by the coupler 26, the shaft 23 comprisedof the unit shafts 23a can be rotated by a driving mechanism 31 fordriving the intake control valve 20 so that first intake passage 17 canbe opened or closed.

Hereinafter, description of the intake control valve driving mechanism31 will be given, with reference to FIGS. 8 to 10.

In FIG. 8 showing the state that the intake control valve drivingmechanism 31 is installed on the exterior surface of the manifold 11,the driving mechanism 31 comprises an actuator 32 incorporating adiaphragm (not shown) therein, a rod 33 being connected to the diaphragmof the actuator 32 and movable axially reciprocally and a lever 35rotatably connected to the rod 33 at its one end by a pin 34 and fixedto the shaft 23 at its other end so as to be rotated by the movement ofthe rod 33 and to transmit a rotation force to the shaft 23. Theactuator 32 is secured to a bracket 36 fixed to the outer surface wallof the intake manifold 11.

A stopper 37 for restricting a rotational range of the lever 35 is alsodisposed on the outer surface wall of the intake manifold 11 in order tocontrol the opening degree of the intake control valve 20, when thelever 35 is rotated due to the axial movement of the rod 33.

FIGS. 9A and 9B illustrate an opened state and a closed state of theintake control valve 20, respectively.

In FIG. 10, a solenoid valve 41 is energized by signals from anelectronic control unit 40 connected to the engine 13, the signals beingfluctuated by the revolutions of the engine 13, and the diaphragm of theactuator 32 is activated by the ON/OFF operation of vacuum in a vacuumtank 42, which operation is done by the solenoid valve 41, thereby tomove the rod 33 axially and to rotate the lever 35 so that the intakecontrol valve 20 may rotate in order to open or shut the first intakepassage 17.

When the engine 13 operates at high speed, as shown in FIG. 9A, theintake control valve 20 is in the opened state, and thus air flows fromthe intake section 12 directly to the connecting passage 14 through thefirst intake passage 17, as shown in FIG. 7. On the other hand, when theengine 13 operates at low speed, as shown in FIG. 9B, the intake controlvalve 20 is in the closed state, and thus air flows from the intakesection 12 to the connecting passage 14 through the second intakepassage 18.

As described above, the intake apparatus of the engine according to thepresent invention can be manufactured with a simple structure and canenhance the intake efficiencies of the engine at low and high speeds byoperating the intake control valve to close or open the first intakepassage automatically in accordance with the variations of therevolutions of the engine, thereby to lengthen or shorten the intakepassage.

Also, since the shaft to which several intake control valves are fixedcomprises at least two unit shafts coupled to each other with a gap, anaxial thermal expansion of the shaft due to the high heat of the enginecan be absorbed thereby to prevent the contact or interference of theshaft with the inner surface wall of the intake manifold when operatingthe intake control valve.

Further, the driving mechanism for driving the intake control valve canbe made compact, and accordingly reliability in operating the intakecontrol valve is improved.

I claim:
 1. An intake apparatus of an engine(13) having an intakemanifold(11) wherein either a short intake passage or a long intakepassage is selected in accordance with the revolutions of theengine(13), characterized in that an intake section(12) into which airflows from air cleaner is provided within the intake manifold(11), apartition wall(16) is installed concentrically with a circular intakemanifold casing(15) surrounding the intake section(12) with respect tothe intake section(12), between the intake manifold casing(15) and theintake section(12), an intake control valve(20) is switchably arrangedbetween an upper end(16a) of the partition wall(16) and a bentportion(14a) of the intake manifold(11), characterized in that at leasttwo unit shafts(23a) are spaced apart from and connected with each otherto form a shaft(23) to which the intake control valve(20) is fixed,thereby to absorb axial thermal expansion of the shaft(23) due to hightemperature of the engine(13), and characterized in that a drivingmechanism(31) for driving the intake control valve(20) comprises anactuator(32) energized by a solenoid valve(41), a rod(33) connected tothe actuator(32) so as to move axially and a lever(35) rotatablyconnected at its one end to the rod(33) by means of a pin(34) andsecured at its other end to the shaft(23).
 2. The intake apparatus asclaimed in claim 1, characterized in that two unit shafts(23a) areconnected with each other by means of a coupler(26).
 3. The intakeapparatus as claimed in claim 2, characterized in that each of the unitshafts(23a) is provided at one of the opposite ends thereof with aconnection portion having a pair of semicircular protrusions(23b) whichare apart from each other.
 4. The intake apparatus as claimed in claim3, characterized in that the actuator(32) incorporates a diaphragmtherein, and the solenoid valve(41) is energized by signals from anelectronic control unit(40) so as to turn the vacuum in a vacuumtank(42) ON or OFF, thereby to activate the diaphragm of theactuator(32).
 5. The intake apparatus as claimed in claim 4,characterized in that the actuator(32) is secured to a bracket(36) fixedto an outer surface wall of the intake manifold(11), and a stopper(37)for restricting a rotational range of the lever(35) is disposed on theouter surface wall of the intake manifold(11) in order to control anopening degree of the intake control valve(20).